Measurement Of Hyperpolarizability Research Articles

Synthesis, conformational study and DFT analysis of novel nonlinear optically active 2r,6c-diaryl-3t-methylpiperidin-4-one N-(2′-furoyl)hydrazones

A series of nonlinear optical (NLO) active 2-furoic acid hydrazide derivatives, 2r,6c-diaryl-3t-methylpiperidin-4-one N-(2′-furoyl)hydrazones (6–10), were synthesized. The structures of these hydrazones were confirmed unambiguously by Fourier transform infrared spectroscopy, mass spectrometry, elemental analysis, 1H, 13C, HOMO-COSY, HSQC, and HMBC nuclear magnetic resonance spectroscopy. The piperidine core of all the targeted hydrazones (6–10) adopted the chair conformation with the equatorial orientations of all the substituents and the ‘E’ configuration about the C=N bond observed. Density functional theory using the B3LYP/6–31G(d,p) level of theory indicated that all hydrazones favor the ‘E’ isomer state. The Mulliken population, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) surfaces, and reactivity parameters were also evaluated and showed a good correlation with the experimental data. The efficiency of hydrazones (6–10) in terms of the nonlinear optical (NLO) activity was proven, and the hydrazones (6–10) showed higher NLO activity compared to that of the reference molecule, as determined by the molecular hyperpolarizability measurements. The structural, spectral, and electrochemical properties were also determined, and DFT analysis was consistent with the experimental outcomes. The FMO, MEP, and reactivity parameter analyses revealed intramolecular charge transfer and high reactive features, leading to superior NLO property of hydrazones (6–10).

Normal Mode Analysis, Electronic Descriptors, NLO Properties 8 Molecular Docking of "Butein, 2',3,4,4'- Tetrahydroxychalcone: A DFT approach"

Study of modern medicine is a flourishing field with activity revolving around the identification, characterization and assessment of therapeutic potential of phytochemicals in various disease conditions. Chalconoids, being prominently present in various medicinal herbs are being widely studied to unravel the molecular mechanisms associated with their effects. This paper describes the molecular structure of well known compound “(Butein, 2',3,4,4'- Tetrahydroxychalcone [C15H12O5]”, which has been optimized and its structural parameters have been calculated by DFT/B3LYP method using 6-311++G(d,p) basis set. The fundamental vibrational wavenumbers and their intensities were calculated and a good agreement between the observed FTIR spectrum and scaled calculated wavenumbers has been achieved. The electronic properties of the compound are explained using HOMO-LUMO and MEPS descriptors. The Non-Linear Optical parameters (NLO) are discussed using electrical parameters like electric dipole moment, molecular polarizability and hyperpolarizability measurements. We have done the molecular docking analysis also, in order to get a better perception into its observed physiological effects which are a prerequisite for determining its therapeutic potential. We hereby report a strong interaction of butein with the protein 1OG6, an enzyme of cytochrome P450 series designated CYP2C9 which is intricately involved in oxidative metabolic pathways. This provides a plausible mechanism for anti-oxidant properties of butein.

Synthesis, spectroscopic characterization, optical, second harmonic generation and DFT analysis of 4-isopropylbenzaldehyde derived hydrazone

In this work, a new hydrazone (E)-N'-(4-isopropylbenzylidene)-4-methoxybenzohydrazide (IBMB) was synthesized via condensation of 1:1 molar ratio of 4-isopropylbenzaldehyde and 4-methoxybenzohydrazide in ethanol. The molecular structure, composition and thermal property of IBMB were analyzed using FT-IR, NMR (1H and 13C), GC–MS, powder XRD, elemental analysis and TG/DTA techniques. The structure was elucidated by single crystal XRD analysis and the crystals belong to orthorhombic system with noncentrosymmetric space group P212121, resulting in highly translucent and nonlinear optical properties. The direct and indirect bandgap energies were evaluated by utilizing Kubelka–Munk algorithm. The efficiency of IBMB in terms of nonlinear optical (NLO) activity was verified and the hydrazone displayed higher NLO activity compared to that of reference materials, as determined by second harmonic generation and molecular hyperpolarizability measurements. Computational studies using density functional theory (DFT) at B3LYP/6–31G(d,p) level of theory were performed for elucidation of the structural parameters, Mulliken population analysis, frontier molecular orbital analysis, UV–Vis absorption spectra and NLO properties of IBMB. Consequently, a good concurrence between the experimental and the DFT results was achieved. Global reactivity parameters were determined using the frontier molecular orbital energies and revealed that IBMB was reasonably stable and more reactive. Mulliken population, Hirshfeld surfaces and fingerprint plot analyses confirmed the presence of inter and intramolecular interactions, contributing superior nonlinearity of crystals.

Beam deflection measurement of bound-electronic and rotational nonlinear refraction in molecular gases.

A polarization-resolved beam deflection technique is used to separate the bound-electronic and molecular rotational components of nonlinear refractive transients of molecular gases. Coherent rotational revivals from N(2), O(2), and two isotopologues of carbon disulfide (CS(2)), are identified in gaseous mixtures. Dephasing rates, rotational and centrifugal distortion constants of each species are measured. Polarization at the magic angle allows unambiguous measurement of the bound-electronic nonlinear refractive index of air and second hyperpolarizability of CS(2). Agreement between gas and liquid phase second hyperpolarizability measurements is found using the Lorentz-Lorenz local field correction.

Liquid–solid interfaces: structure and dynamics from spectroscopy and simulations

Liquid–solid interfaces: structure and dynamics from spectroscopy and simulations

Spectral characterization of a non-centrosymmetric organic compound: D-(–)-alanine

The crystal growth of D-(–)-alanine (1), a non-centrosymmetric solid is reported. It was characterized by NMR, infrared, Raman, UV–Vis–NIR and CD spectra. Experimental vibrational frequencies are compared with theoretically calculated values. Second harmonic generation (SHG) and first hyperpolarizability measurements are reported.

Structure of the Pyridine–Chloranil Complex in Solution: A Surprise from Depolarized Hyper-Rayleigh Scattering Measurements

In this article, we report the structure of a 1:1 charge transfer complex between pyridine (PYR) and chloranil (CHL) in solution (CHCl(3)) from the measurement of hyperpolarizability (β(HRS)) and linear and circular depolarization ratios, D and D', respectively, by the hyper-Rayleigh scattering technique and state-of-the-art quantum chemical calculations. Using linearly (electric field vector along X) and circularly polarized incident light, respectively, we have measured two macroscopic depolarization ratios D = I(X,X)(2ω)/I(X,Z)(2ω) and D' = I(X,C)(2ω)/I(Z,C)(2ω) in the laboratory fixed XYZ frame by detecting the second harmonic (SH) scattered light in a polarization resolved fashion. The stabilization energy and the optical gap calculated through the MP2/cc-pVDZ method using Gaussian09 were not significantly different to distinguish between the cofacial and T-shape structures. Only when the experimentally obtained β(HRS) and the depolarization ratios, D and D', were matched with the theoretically computed values from single and double configuration interaction (SDCI) calculations performed using the ZINDO-SCRF technique, we concluded that the room temperature equilibrium structure of the complex is cofacial. This is in sharp contrast to an earlier theoretical prediction of the T-shape structure of the complex.

Nonlinear multicontrast microscopy of hematoxylin-and-eosin-stained histological sections

Imaging hematoxylin-and-eosin-stained cancerous histological sections with multicontrast nonlinear excitation fluorescence, second- and third-harmonic generation (THG) microscopy reveals cellular structures with extremely high image contrast. Absorption and fluorescence spectroscopy together with second hyperpolarizability measurements of the dyes shows that strong THG appears due to neutral hemalum aggregation and is subsequently enhanced by interaction with eosin. Additionally, fluorescence lifetime imaging microscopy reveals eosin fluorescence quenching by hemalums, showing better suitability of only eosin staining for fluorescence microscopy. Multicontrast nonlinear microscopy has the potential to differentiate between cancerous and healthy tissue at a single cell level.

Predicting the Frequency Dispersion of Electronic Hyperpolarizabilities on the Basis of Absorption Data and Thomas−Kuhn Sum Rules

Successfully predicting the frequency dispersion of electronic hyperpolarizabilities is an unresolved challenge in materials science and electronic structure theory. We show that the generalized Thomas-Kuhn sum rules, combined with linear absorption data and measured hyperpolarizability at one or two frequencies, may be used to predict the entire frequency-dependent electronic hyperpolarizability spectrum. This treatment includes two- and three-level contributions that arise from the lowest two or three excited electronic state manifolds, enabling us to describe the unusual observed frequency dispersion of the dynamic hyperpolarizability in high oscillator strength M-PZn chromophores, where (porphinato)zinc(II) (PZn) and metal(II)polypyridyl (M) units are connected via an ethyne unit that aligns the high oscillator strength transition dipoles of these components in a head-to-tail arrangement. We show that some of these structures can possess very similar linear absorption spectra yet manifest dramatically different frequency-dependent hyperpolarizabilities, because of three-level contributions that result from excited state-to-excited state transition dipoles among charge polarized states. Importantly, this approach provides a quantitative scheme to use linear optical absorption spectra and very limited individual hyperpolarizability measurements to predict the entire frequency-dependent nonlinear optical response.

Synthesis, characterization, and hyperpolarizability measurements of main‐chain azobenzene molecules

AbstractA series of new AB type azobenzene monomers based on various substituted phenols and higher order fused/extended aromatic rings were synthesized and their hyperpolarizability tensor β determined by hyper‐Rayleigh scattering (HRS) measurement in methanol. The electron donor (OH) and acceptor units (COOH) were kept constant in the series, but the effective conjugation length was varied by varying the number and position of substituents as well as the number of aromatic rings. The effect of substitution of the phenolic ring on the β value was investigated and it was found to range from 15 × 10−30 to 42 × 10−30 esu. The effect of intramolecular hydrogen bonding on the nonlinear optical (NLO) property was also examined. The nonlinearity was in the following order of phenol derivative: α‐naphthol > phenyl phenol > 2,6‐dimethyl phenol > o‐cresol > cardanol > phenol > β‐naphthol. The unusually low values for the β‐naphthol‐based chromophore compared with its isomer (α‐naphthol) could be rationalized based on hydrogen bonding of the o‐hydroxyl group with the β nitrogen of the azo bridge. These azobenzene NLO chromophoric monomers were polymerized to form main‐chain polymers with a head to tail structure. The polymers had high thermal stability and rather low solubility in common organic solvents. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4455–4468, 2005

Investigation of new push–pull pyridine-1-oxide derivatives as 1D NLO chromophores with vanishing dipole moment

The non-linear optical properties of new one-dimensional (1D) hyperpolarizable chromophores bearing a pyridine-1-oxide donor group and a 4-nitrophenyl acceptor group, linked by CC or NN double bonds have been studied. These molecules present a true intramolecular donor/acceptor charge transfer (ICT) leading to high β hyperpolarizability, but unlike the classical ICT chromophores exhibit a vanishing dipole moment μ. Such a property can lead to a better control of the non-centrosymmetric alignment of the hyperpolarizable chromophores in the solid state, as observed previously in 3-methyl-4-nitropyridine-1-oxide crystals (POM). Due to the lack of dipole moment β cannot be measured by EFISHG. In this paper, the synthesis, modeling of μ and β, and hyper-Rayleigh scattering (HRS) hyperpolarizability measurements of 4′-nitro-4-stilbazole- N-oxide and its azo analogue, as two representative chromophores in this series, are reported. The values are compared with these of the polar analogue 4-methoxy-4′-nitrostilbene (MONS). Hartree-Fock calculations confirm their vanishing dipole moment and give β-values in good accordance with those obtained experimentally by HRS. Longer 1D chromophores in this series are currently under investigation.

Measurement and analysis of molecular hyperpolarizability in the two-photon resonance regime

The frequency dependent hyperpolarizability of typical donor–acceptor organic nonlinear optical molecules is commonly represented by a nonresonant two-level model, first presented by Oudar and Chemla. We discuss how this model can be extended into the resonant regime, including cases where the molecular transition is described by an inhomogeneously broadened peak. A resonant measurement of hyperpolarizability by electric field induced second harmonic generation (EFISH) is demonstrated, as well as the more conventional off-resonance EFISH. The theoretical model correctly predicts both the amplitude and phase of the resonant hyperpolarizability measured by EFISH. We also show that both on-resonance and off-resonance EFISH yield the same hyperpolarizability extrapolated to the zero frequency limit.

General equation for determining the dissociation constants of polyprotic acids and bases from additive properties. Part II. Applications

Dissociation constants of some polyprotic acids and bases are determined from spectrophotometric and reversed-phase high performance liquid chromatographic data. A general equation relating additive properties of acids and bases to the pH of the solution is used for this purpose. The method is tested by applying it to the calculation of overlapping p K as without the prerequisite of measuring the limiting values of the property for the individual species that result from the dissociation of the solute. The possibility of applying the same method to hyperpolarizability measurements is pointed out, and a procedure, based on the general equation, for obtaining the activity coefficients of the ionic species as a function of the ionic strength is also suggested.

Long-wavelength first hyperpolarizability measurements by hyper-Rayleigh scattering

A hyper-Rayleigh scattering (HRS) system based on an optical parametric power oscillator is described. The first hyperpolarizability, beta, of Crystal Violet dye was measured at 1450 and 1500 nm. The resonance-free beta value, beta(0), for this octupole was found to be comparable with that of the dipolar dye Disperse Red 1 but with the nonlinearity-transparency trade-off worse for the octupole. The discrepancy in beta(0) with that reported previously is explained in terms of resonance and the adequacy of the octupolar three-state model. The possibility of dye aggregation by solvent-dependent HRS is investigated.

First hyperpolarizability measurements via hyper-Rayleigh scattering at 1500 nm

A hyper-Rayleigh scattering, HRS, system constructed around an optical parametric power oscillator and allowing wide fundamental wavelength tunability is described in detail. The design of the HRS cell, which may overcome problems inherent with other cell designs, is discussed. The potential of this HRS system for non-resonant first hyperpolarizability, β, determination is highlighted via measurement of a dipolar chromophore at 1500 nm. The magnitude of the non-linearity may be explained by either increased conjugation in the charge-transfer state or by increased magnitude in non-diagonal β-tensor elements.

Nonlinear Optical Properties of Proteins Measured by Hyper-Rayleigh Scattering in Solution

Hyper-Rayleigh scattering has been used to determine the nonlinear optical properties of a chromophore-containing protein in solution. Because the technique of hyper-Rayleigh scattering allows the measurement of hyperpolarizabilities in an isotropic solution without the application of an electric field, this method is ideally suited for the study of proteins that carry a net charge. The observed orientational correlation between the nonlinear optical chromophores in incompletely solubilized protein molecules suggests that guidelines from protein structures can be used for the engineering of supramolecular structures with high optical nonlinearity.

ChemInform Abstract: Two‐Photon Absorption and Second Hyperpolarizability Measurements in Diphenylbutadiene by Degenerate Four‐Wave Mixing.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The effect of the local field on the optical second-harmonic response of mixed liquid crystal-stearic acid monolayers

Optical second-harmonic generation (SHG) from mixed liquid crystal-stearic acid molecular monolayers, as a function of liquid crystal concentration, is reported. It is shown that, in concentrated monolayers, a substantial local-field effect exists which can be described, to a first approximation, by a point dipole model. The apparent molecular hyperpolarizability in pure monolayers of these liquid crystals is reduced by a factor of between six and eight, due to this local field. This is an important consideration in the design of materials for ultra-thin-film nonlinear optical devices. Hyperpolarizability measurements should be made using monolayer films where the active species is diluted by about a factor of ten by a species with negligible polarizability, such as a fatty acid, having first taken care to establish that the active species disperses uniformly. In this way the experimental hyperpolarizability may be directly compared to theoretical values from calculations of isolated molecular clusters. These LB monolayers are ideal model systems for testing theoretical approaches to the local-field problem, and progress in this area is important in understanding the optical response of surfaces and interfaces in general, and those of semiconductors in particular.

Hyperpolarizability of the C60 fullerene cluster

Motivated by a discrepancy of five orders of magnitude between three different hyperpolarizability measurements on the C60 fullerene, we calculated the optical response of this cluster using a tight-binding Hamiltonian and compared the results to those for a benzene molecule. Our Hamiltonian reproduces the linear polarizability and hyperpolarizability of benzene reasonably well. For C60, our calculations of the bare polarizability agree only with two of the optical response measurements and indicate that the corresponding linear and nonlinear response of C60 is much larger than that of C6H6. We find that screening effects decrease this difference strongly, and also reduce the calculated hyperpolarizability of C60 to a value which is two orders of magnitude below the favored measurements.

Heterocyclic azole nonlinear optical chromophores. 1. Donor-acceptor substituted pyrazole derivatives

We have described the synthesis of a variety of 1,3,1,4, and 1,5 donor-acceptor conjugation extended substituted pyrazole derivatives and have studied their spectr6scopic and nonlinear optical properties. These materials are thermally stable and absorb strongly in the UV-visible region, albeit at much shorter wavelengths than comparably substituted cyclic azapolyenes such as 2-pyrazolines. Quadratic hyperpolarizability measurements suggest that the pyrazoles are significantly nonlinear, and that 1,3 and 1,4 substitution is preferred. 1,5 substitution causes a significant drop in the nonlinearity and a blue shift in the long-wavelength absorption maximum, presumably due to a twisting and partial deconjugation of the substituents to relieve unfavorable steric interactions. The experimental results are compared with those predicted by simple “finite field” computational procedures.